GNSS – Structural Integrity Monitoring

CGSIC-USSLS

Seattle WA – August 14th, 2011

Gavin Schrock, PLS – Washington State Reference Network

Managing RTN Geodesy, & Structural Integrity Monitoring

Network Integrity – Relative Integrity

Network Integrity - Registration to NSRS (NGS)

Regional Tectonics – Partnering with Academia

Monitoring - Dams, Bridges, Structures, Slides and …

National CORS - HAHD

Ross Slide

Viaduct

Tolt Dam

520 Ross Dam

(in progress)

Municipal Tower

WSRN-CWU Monitoring Initiative

Pacific Northwest

Regional Tectonic Activity

0 500 km 1000 km

Long Baseline RME & PPE

Tolt Dam

0 100 km 200 km

Medium Baseline RME & PPE

Tolt Dam

0 100 km 200 km

Medium Baseline RME & PPE Monitoring of Localized RTKE Bases

Tolt Dam

Primary Network Monitored – NGS, Academia, TIM/VRSNet

GIMI – GNSS Integrated Monitoring Initiative

Localized Subnets Monitored in TIM/VRSNet

GIMI – GNSS Integrated Monitoring Initiative

Localized Subnets Monitored in TIM/VRSNet

Constraining CORS for Localized Monitoring

GIMI – GNSS Integrated Monitoring Initiative

Registration to External Reference Framework

NSRS – NAD83 (CORS96) Epoch 2002.00 (et al)

NSRS – NAD83-2011 Epoch 2010.00

GIMI – GNSS Integrated Monitoring Initiative

Select NOAA-National Geodetic Survey CORS

Network Integrity – Relative Integrity

• Registration to External Reference Framework

IGS sites – PPS of Static Data and/or JPL PPP positions held

Registration to ITRF and/or SNARF utilizing Post-Processed and Rapid Motion Engine(s)

GIMI – GNSS Integrated Monitoring Initiative

Trimble Integrity Manager

NME - Network Motion Engine RME - Rapid Motion Engine

PPE – Post-Processing Engine RTKE – Real-Time Kinematic Engine

WSRN Plan for NAD83-CORS96 to NAD2011 Migration

Dual System for 12-24 Months: VRSNet – One set of servers running NAD2011 (multi-year solution) GPSNet – One set of servers running NAD83-CORS96 Epoch 2002.00

Why Should Folks be Using RTN for

Monitoring and Machine Control?

Structural Integrity

Dam Monitoring - Tolt Structural Integrity Monitoring mm Precisions in Real-Time

520 Floating Bridge Alaskan Way Viaduct Howard Hansen Dam

Ross Rockslide

Ross Dam Rockslide

Rock Promontory

Transmission Tower

Rock Promontory

Slide

Dam

CORS

Powerhouse

Transmission Tower

Slide – Spring 2010 Stabilization will require blasting

and scaling

Tower Footing on Rock Promontory Monitored & Solar Array

Ross Dam Rockslide

Transmission Tower

Test Blasting – May 2010

Ross Dam Rockslide

TC

TS

TN

BN

BS

LSIG

Test

Zoned Earthfill Embankment – 61m x 300m

Tolt Dam

Motion Test on Translation Table

Bench Tests - 2008

Tolt Dam

Conventional Monitoring – Annually (June)

Tolt Dam

August 2008 – January 2009

Tolt Dam

Reservoir Level and Sensor Displacement

Tolt Dam

Possible Movement due to Seismic Events

USGS Seismograph

Tolt Dam

Central

Washington

University

Seattle

Public

Utilities

US Army Corps

of Engineers

Howard A. Hanson Dam

Integrated Monitoring Study

Software and Hardware Tests

Seattle Public Utilities

May 22nd 2012

Challenges:

No Budget – Low Budget

Borrowed Equipment

Surplus Equipment

No Telecommunications Access

Triumphs:

Outstanding Support from USACE On-site crew!

Low cost radio network

Outstanding software and hardware performance

Outstanding vendor technical support

• Green River, Washington State

• Legacy of Green River Flooding

• Earthen Zone-Fill Dam Completed 1961

• Cycle of Flooding Ends

• USACE Managed

• Tacoma Water – Water Purification and Distribution System

• January 2009 High Runoff and Seepage in Right Abutment. Water Released. Downstream Flooding

• Ongoing Rehab – Grout Curtain at Right Abutment

• Nov 2010 – Integrated Monitoring Study Begins

Howard Hanson Dam

Howard Hanson Dam

Integrated Monitoring Study Goals • Study GNSS Monitoring Capabilities • Provide Independent Deflection Data • Test Integrated GNSS/Optical Capabilities • Add GNSS Sensors to Regional RTN, Earthquake Study, and Geodetic

Networks • Compare Results with Other Earthen Dams using Similar Methods

(e,g, Tolt Dam) • Test Various GNSS Motion Engines • Geophysical Sciences Lateral Studies • Test Alarm Thresholds • NOT to be currently used as an alarm system

32 km

25 km

15 km

Howard Hanson Dam

WSRN & NGS CORS - “HAHD”

CORS - “BDRH”

Howard Hanson Dam

Intake Tower

Exposed Bedrock

Howard Hanson Dam

BDRH

FND2

FND1

EMBR

EMBC

EMBL

TWR1

BRDG

SPWY

Howard Hanson Dam

BDRD

BDRH FND2

FND1

EMBR

EMBC

TWR1

SPWY

GNNS SIGNAL BOX COAX RADIO LINK

BRDG

EMBL

BDRD

Howard Hanson Dam

BDRH FND2

FND1

EMBR

EMBC

TWR1

SPWY

BRDG

EMBL

BDRD

Howard Hanson Dam

Drill-Brace

Mount

Construction

BDRH

Broadband

Comms Link

Signal Box

Right

Embankment

Fish-Passage

Excavation

Next to Tower

Bridge

Mount

Tower

Mount Tower &

Bridge

Spillway

Mount

Post

Mount

USACE ONSITE SERVERS

SPU

CWU

Processing Strategy • Dual servers onsite • External comms for SPU/CWU • NO external connection to USACE IT • Science processing at CWU • Processing backup at SPU • Web Reporting Application for USACE • Sensor streams bi-directional to CWU/SPU

Howard Hanson Dam

Howard Hanson Dam

Example- 3.4 Earthquake 45km away –May 2010

Howard Hanson Dam

Example- 3.4 Earthquake 45km away –May 2010

Example:

Raising Pool Level

May-July 2010

Excerpts from T4D User Interface

Howard

Hanson Dam

Howard Hanson Dam

Web Reporting Interface

Howard Hanson Dam Web Reporting Interface

Alarm Modules

Operational Alarms

System Elements: Unavailable

Performance Thresholds

System Events: Conditions Change

Conditions Persist

Conditions Return to Normal

System Triggers: Email

SMS

Batch/Scripts

Reboot/Power Management

Alarm Modules

Performance Alarms

Warning Thresholds: X, Y, Z

Velocity

2D & 3D

Condition Persists

Alert Thresholds: X, Y, Z

Velocity

2D & 3D

Condition Persists

Disarm Thresholds: X, Y, Z

Velocity

2D & 3D

Condition Persists

Actions: Email, SMS

Batch/Scripts

Controls/Power Management

Howard Hanson Dam

TOTAL STATION

Robotic

Total

Station

Optical/GNSS Integration

BACKSITE

GNSS

Antenna &

Target for

Control

Optical/GNSS Integration

Motion Engines

Motion Engines

Motion Engines

Sudden Motion

First Check

Minutes Trends

RTK Motion

Second Check

Hour Trends

Network Motion

Third Check

Day Trends

Motion Engines

Post-Processing Engine

Long-Term Trending

Motion Engines - Optical

Engine Filter

Reaction time for

50%

of movement

Reaction Time

100%

of movement

RTK Unfiltered - 0 sec

RTK Weighted mean (1 min) - 1 min

RTK Kalman sudden - 30 sec

RTK Kalman moderate - 6 min

Rapid Motion unfiltered 1 sec > 15 min

Rapid Motion Weighted mean (1 min) 45 sec > 15 min

Rapid Motion Kalman sudden 5-10 sec > 15 min

Rapid Motion Kalman moderate 5 min > 30 min

Network

Motion

N/A 2 h 12 – 24 h

Motion Engines

• Kalman filter: – Static

• Convergence time: 24 h

• Reaction time: days

– Moderate Movement

• Convergence time: 1-2 h

• Reaction time: minutes

– Sudden Movement

• Convergence time: ~ 0

• Reaction time: seconds

– Custom

• Depending on parameters

Motion Engines - Filters

Analysis Tools

Howard Hanson Dam Mapping Options

Howard Hanson Dam

Integrated Monitoring Study – Lesson Learned

• Confirmation of Tolt Findings

• Communications Options Explored

• When you have to save money, you will find ways to.

• Can build cheaper then thought, but not for as little as we spent

• Server simplicity/redundancy a plus

• Motion engine behaviors refined

• Integrated optical feasible and a huge plus

Full implementation suspended indefinitely due to budget constraints. Minimal monitoring (GNSS only) to continue.

Elevated Highway

Floating Bridge and High-Rise

Wind Load on Floating Bridge

Floating Bridge